# PHP-CS-Fixer — Automatic PHP Code Style Fixer

> A tool to automatically fix PHP coding standards issues. Supports PSR-1, PSR-2, PSR-12, PER, Symfony, and custom rule sets to enforce consistent code style across teams and CI pipelines.

## Install

Save in your project root:

# PHP-CS-Fixer — Automatic PHP Code Style Fixer

## Quick Use
```bash
composer global require friendsofphp/php-cs-fixer
php-cs-fixer fix src/
```

## Introduction
PHP-CS-Fixer scans PHP source files and automatically rewrites them to comply with a chosen coding standard. It eliminates style debates in code review by programmatically enforcing rules from PSR-12, PER, Symfony conventions, or any custom configuration.

## What PHP-CS-Fixer Does
- Fixes PHP files to conform to PSR-1, PSR-2, PSR-12, PER, and Symfony coding standards
- Supports over 200 individual fixers covering spacing, alignment, imports, phpdoc, and control structures
- Runs in dry-run mode to report violations without modifying files
- Integrates with CI/CD pipelines to block merges that violate style rules
- Allows project-level configuration via a `.php-cs-fixer.dist.php` file

## Architecture Overview
PHP-CS-Fixer parses each PHP file into a token stream using PHP's built-in tokenizer, applies an ordered chain of fixers to that stream, then writes the corrected tokens back to disk. Fixers are composable and dependency-aware: the tool resolves ordering conflicts automatically so that one fixer's output does not break another's assumptions.

## Self-Hosting & Configuration
- Install globally via Composer or per-project as a dev dependency
- Create a `.php-cs-fixer.dist.php` config file to define rule sets and finder paths
- Use preset rule sets like `@PSR12`, `@Symfony`, or `@PER-CS` as a base, then override individual rules
- Run `php-cs-fixer fix --dry-run --diff` in CI to fail builds on style violations without changing files
- Cache results with `--cache` to skip unchanged files on subsequent runs

## Key Features
- Over 200 fixers covering nearly every aspect of PHP code formatting
- Risky fixers (those that change code behavior) are opt-in and clearly labeled
- Parallel execution support for faster processing of large codebases
- Built-in caching avoids re-processing unchanged files across runs
- Active development with regular releases tracking the latest PHP language features

## Comparison with Similar Tools
- **PHP_CodeSniffer (phpcs/phpcbf)** — sniffs and fixes; PHP-CS-Fixer focuses exclusively on automated fixing with a larger fixer library
- **Laravel Pint** — opinionated wrapper around PHP-CS-Fixer with Laravel-specific defaults
- **Rector** — handles code upgrades and refactoring; PHP-CS-Fixer focuses on style rather than logic changes
- **PHPStan/Psalm** — static analysis tools that find bugs; PHP-CS-Fixer addresses formatting only
- **Prettier PHP Plugin** — Prettier ecosystem; PHP-CS-Fixer offers deeper PHP-specific rule coverage

## FAQ
**Q: Can I use PHP-CS-Fixer alongside PHPStan or Psalm?**
A: Yes. PHP-CS-Fixer handles formatting while PHPStan and Psalm handle static analysis. They complement each other in CI pipelines.

**Q: Does it support PHP 8.x syntax?**
A: Yes. Fixers are updated regularly to handle PHP 8.0 through 8.4 features including attributes, enums, readonly properties, and intersection types.

**Q: How do I share configuration across multiple projects?**
A: Create a shared Composer package containing your `.php-cs-fixer.dist.php` config and install it as a dev dependency in each project.

**Q: Will it change the behavior of my code?**
A: Standard fixers only change formatting. Risky fixers that could alter behavior (e.g., renaming functions) must be explicitly enabled.

## Sources
- https://github.com/PHP-CS-Fixer/PHP-CS-Fixer
- https://cs.symfony.com/

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Author: AI Open Source